Cessation of dual antiplatelet treatment and cardiac events after percutaneous coronary intervention (PARIS): 2 year results from a prospective observational study

BACKGROUND

Dual antiplatelet therapy (DAPT) cessation increases the risk of adverse events after percutaneous coronary intervention (PCI). Whether risk changes over time, depends on the underlying reason for DAPT cessation, or both is unknown. We assessed associations between different modes of DAPT cessation and cardiovascular risk after PCI.

METHODS

The PARIS (patterns of non-adherence to anti-platelet regimens in stented patients) registry is a prospective observational study of patients undergoing PCI with stent implantation in 15 clinical sites in the USA and Europe between July 1, 2009, and Dec 2, 2010. Adult patients (aged 18 years or older) undergoing successful stent implantation in one or more native coronary artery and discharged on DAPT were eligible for enrolment. Patients were followed up at months 1, 6, 12, and 24 after implantation. Prespecified categories for DAPT cessation included physician-recommended discontinuation, brief interruption (for surgery), or disruption (non-compliance or because of bleeding). All adverse events and episodes of DAPT cessation were independently adjudicated. Using Cox models with time-varying covariates, we examined the effect of DAPT cessation on major adverse events (MACE [composite of cardiac death, definite or probable stent thrombosis, myocardial infarction, or target-lesion revascularisation]). Incidence rates for DAPT cessation and adverse events were calculated as Kaplan-Meier estimates of time to the first event. This study is registered with ClinicalTrials.gov, number NCT00998127.

FINDINGS

We enrolled 5031 patients undergoing PCI, including 5018 in the final study population. Over 2 years, the overall incidence of any DAPT cessation was 57·3%. Rate of any discontinuation was 40·8%, of interruption was 10·5%, and of disruption was 14·4%. The corresponding overall 2 year MACE rate was 11·5%, most of which (74%) occurred while patients were taking DAPT. Compared with those on DAPT, the adjusted hazard ratio (HR) for MACE due to interruption was 1·41 (95% CI 0·94-2·12; p=0·10) and to disruption was 1·50 (1·14-1.97; p=0·004). Within 7 days, 8-30 days, and more than 30 days after disruption, adjusted HRs were 7·04 (3·31-14·95), 2·17 (0·97-4·88), and 1·3 (0·97-1·76), respectively. By contrast with patients who remained on DAPT, those who discontinued had lower MACE risk (0·63 [0·46-0·86]). Results were similar after excluding patients receiving bare metal stents and using an alternative MACE definition that did not include target lesion revascularisation.

INTERPRETATION

In a real-world setting, for patients undergoing PCI and discharged on DAPT, cardiac events after DAPT cessation depend on the clinical circumstance and reason for cessation and attenuates over time. While most events after PCI occur in patients on DAPT, early risk for events due to disruption is substantial irrespective of stent type.

FUNDING

Bristol-Myers Squibb and Sanofi-Aventis.

Adverse event rates following primary PCI for STEMI at US and non-US hospitals: three-year analysis from the HORIZONS-AMI trial

AIMS

To examine outcomes in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) at US sites versus sites outside the US (OUS).

METHODS AND RESULTS

In the HORIZONS-AMI trial 3,602 STEMI patients in 11 countries were randomised to primary PCI with bivalirudin versus heparin + glycoprotein IIb/IIIa inhibitors. US patients (n=814) had more diabetes, prior infarction, prior bypass surgery, and renal insufficiency. OUS patients (n=2,788) had longer door-to-balloon times, more radial access, fewer bypass surgeries, and were discharged more often on beta-blockers and statins. At three years US patients had higher mortality (9.7% vs. 6.0%, p=0.0003), reinfarction (10.2% vs. 6.4%, p=0.001), major adverse cardiac events (MACE; 28.2% vs. 20.1%, p<0.0001), major bleeding (16.9% vs. 6.4%, p<0.0001) and net adverse clinical events (NACE; 36.6% vs. 23.8%, p<0.0001), which persisted after adjusting for baseline risk.

CONCLUSIONS

In the HORIZONS-AMI trial, STEMI patients undergoing primary PCI at US versus OUS sites had higher rates of adverse events, which persisted after adjusting for baseline risk. The reasons for these differences are not clear but may be due to unmeasured confounders, different thresholds for event reporting, or valid differences in systems of care and treatments.

Are adverse events following an invasive strategy in patients with non-ST-segment elevation acute coronary syndromes more frequent at US sites versus non-US sites? Analysis from the ACUITY trial

OBJECTIVE

To compare outcomes between US and non-US (OUS) sites in patients with non ST-elevation acute coronary syndromes (NSTEACS) and to evaluate potential reasons for differences in outcomes.

BACKGROUND

There are little data comparing outcomes at US versus OUS sites in patients with NSTEACS managed with an invasive strategy.

METHODS

The ACUITY trial randomized 13,819 patients with NSTEACS in 17 countries to an invasive approach with one of three strategies: (1) heparin plus glycoprotein platelet inhibitors (GPI), (2) bivalirudin plus GPI, or (3) bivalirudin alone.

RESULTS

US patients were more often female, were younger, heavier, and had more diabetes, prior myocardial infarction (MI), and prior bypass surgery. US patients were less often treated with percutaneous coronary intervention but had more frequent drug-eluting stent use. US patients had lower mortality and higher MI rates at 30 days and 1 year and higher composite ischemic outcome at 30 days. After adjusting for differences in baseline variables, US patients had higher rates of MI and composite ischemic outcome at 30 days and higher rates of MI at 1 year {HR [95% confidence interval (CI)] = 1.36 [1.18-1.56], P < 0.0001} with no differences in mortality. There were no differences in treatment effects comparing bivalirudin with the other strategies between US and OUS sites.

CONCLUSIONS

US versus OUS patients with NSTEACS had higher adjusted rates of MI and ischemia. The reasons for these differences are not clear but may be due to unmeasured confounders, different thresholds for event reporting, or valid differences in systems of care which may impact outcomes.